Almost 1,600 people applying for welfare benefits in Florida have declined to undergo drug testing, which is required by a new state law. According to state officials, less than one percent of the 7,028 welfare applicants who underwent screening tested positive for drugs since the law went into effect in July.

Since so many applicants refused to take a drug test, it is difficult to draw conclusions from these findings, according to the Associated Press. A majority of positive drug tests were for marijuana.

The American Civil Liberties Union has filed a lawsuit to challenge the new law. The lawsuit asserts the law’s drug-testing requirement represents an unconstitutional search and seizure.

The Florida law requires applicants to be responsible for the cost of the screening. They can recover the costs if they qualify for assistance. Under the law, applicants who fail the drug screen can designate another person to receive the benefits on behalf of their children. That person must also undergo drug testing.

According to the article, a person who fails the drug test is not eligible for welfare for one year. Passing a drug course can cut that time down to six months. A person who fails a second drug test is ineligible for benefits for three years.

Supporters of the law say it prevents taxpayer money from being spent on drugs. Critics say the cost of the test—$25 to $35—may be too high for some applicants, or they may not be able to easily get to a testing facility.

Florida is one of a growing number of states requiring drug testing for recipients of welfare, food stamps, unemployment and other benefits. Legislators in three dozen states have proposed drug testing this year for people who receive welfare benefits.